Winch braking mechanism

ABSTRACT

A winch having an inertia responsive brake, and a velocity responsive actuator means also disposed in actuating relation to the said brake, wherein the actuator means is, at least to some extent, inertia responsive.

[ 1 July4,l972

United States Patent Worstell et al.

[54] WINCH BRAKING MECHANISM References Cited UNITED STATES PATENTS [73] Assignee: Dillingham Corporation, Honolulu,l-lawaii 2 029 d: D I 9, 3,433,332 Blalll'lunun... [22] cc 3,572,482 Kalpaset [21] 96,624

Related US. Application Data Continuation of S61. No. 800,654, Feb. abandoned.

Appl. No.:

Primary Examiner-George E. A. Halvosa AttorneyBuckhorn, Blore, Klarquist & Sparkman ABSTRACT A winch having an inertia responsive brake, and a velocity responsive actuator means also disposed in actuating relation 52 u.s.ct................................iss/i34,187/38,138/105,

88/187 to the said brake, wherein the actuator means is, at least to [SI] l88/105,180,18l A, l87,l34;

some extent, inertia responsive.

[58] Field ofSearch 254/187 R; 182/75; l87/38 4Claims, I0 Drawing Figures PATENTEIJJUL 4 I572 SHEET 10F 3 INVENTORS WAYNE C, WORSTELL C. COUSNS EUGENE A COOLEY BUCKHORN, SLOPE, KLAROU/ST 8 SPAR/(MAN RICHARD ATTORNEYS PATENTEDJULM 1972 SHEET 2 0F 3 FIG, 4

INVENTORS WAYNE C, WORSTELL RICHARD C COUSINS EUGENE A COOLEY Hue/mom, 620/?5, KLAROU/ST a SPAR/(MAN ATTORNEYS PATENTED L 412 2 3. 574,1 19

saw 3 or a INVENTORS WAYNE C. WORSTE RICHARD C COUSI EUGENE A. COOL BUCK/10PM SLOPE, KLAROU/ST 8 SPAR/(MAN ATTORNEYS WINCH BRAKING MECHANISM This application is a continuation of application, Ser. No. 800,654, filed Feb. [9, I969, now abandoned.

BODY OF APPLICATION This invention relates to cable winches and will be described in connection with suspended staging, although the invention has wider application.

At present, it is common practice, in winch operated suspended staging, to provide braking means to prevent too rapid descending movement of the staging. This braking means has been inertia responsive, and thus is not responsive to the velocity of the drum. Thus, if for any reason, rapid acceleration of the drum fails to cause actuation of the braking means, damage and injury can result. In addition, if the descending velocity of the staging can attain an undesirable magnitude without the acceleration exceeding the safety limit, this could also cause damage and injury.

It is a main object of the present invention to provide velocity responsive braking means for a winch, and particularly a velocity responsive actuator to actuate the inertia brake in the event it is not otherwise actuated, and to aid the inertia responsive means to actuate said brake.

Another object is to provide a velocity responsive actuator which, at least to some extent, is inertia responsive.

Various other objects of the invention will be apparent from the following description taken in connection with the accompanying drawings wherein:

FIG. I is a perspective view of a suspended staging incorporating the concepts of the present invention;

FIG. 2 is an enlarged fragmentary vertical sectional view taken along line 22 of FIG. 1 showing the braking end of the drum;

FIG. 2A is a fragmentary 2A-2A ofFlG. l;

FIG. 3 is a fragmentary end elevational view taken in the direction of the arrows 3-3 of FIG. 2 and on a scale smaller than that employed in FIG. 2;

FIG. 4 is a vertical sectional view taken along lines 4-4 of FIG. 2, FIG. 4 being on the same scale as FIG. 3;

FIG. 5 is a fragmentary vertical sectional view taken along lines 5-5 of FIG. 2, FIG. 5 being taken on the same scale as FIGS. 3 and 4;

FIG. 6 is a fragmentary sectional view taken along line 6-6 of FIG. 5, FIG. 6 being on a slightly enlarged scale as compared to that in FIG. 5;

FIG. 7 is a sectional view taken along line 77 of FIG. 2;

FIG. 8 is a sectional view taken along line 8-8 of FIG. 7; and

FIG. 9 is a midsectional view through a modified form of the actuator.

FIG. I shows a platform or staging ll suspended by cables I3 alongside a building 15. Each cable is reeled in or payed out under the control of a motor-driven winch unit 17. Each winch unit is of the same construction and is shown as having an electric motor 19, although the motor could be hydraulic, internal combustion, etc. The motor is operated by controls (not shown) to drive a winch drum 3| via a speed reduction unit 33. Each drum 3| has an inertia brake which is designed to halt rotation of the drum, and thus halt descending movement of the platform I I, anytime the rate of descent exceeds a predetermined safe rate.

FIG. 2 shows, in section, the braking end of the winch drum. The drum has a drive shaft 35 which is supported by bearings, which in turn are mounted on horizontal members of the frame 41 of the winch unit I7. One of the bearings is shown in FIG. 2 and is labeled 43, and the associated horizontal frame member is labeled 45.

The drum 31 includes a hollow core member 51 which is mounted at its left hand end (as the parts are shown in FIG. 2) on the hub portion 53 of the broke housing 55. The left hand end of the housing is closed by a support plate 57 which has three lugs 59 (FIGS. 2 and 3) fitting in holes in the frame sectional view taken along line member 45. The lug hold the support plate 57 stationary relative to the winch drum 3] (and thus stationary relative to the brake housing 55 which is a part of the drum).

The inertia brake includes a plurality of annular rotary disks 71 (FIGS. 2 and 4) which are keyed to the housing 55 by keys 73 (FIG. 4), and a plurality of interleaved stationary disks 75, which have square holes 77 (FIG. 4) to non-rotatably fit on a square disk support 79. The latter is secured by bolts 8I (FIGS. 2 and 4) to the support plate 57.

The inertia brake includes a mechanism which is responsive to a predetermined accelerating nmvement of the winch drum 3] to force the disks 7] and 75 into tight frictional engagement, whereby they halt rotating movement of the drum. This mechanism includes a pressure plate 91 (FIG. 2) which is equipped with a plurality of pins 93, which are surrounded by compression springs 94, and slidably project through an actuating plate 95. Retainers 96 are provided on the inner ends of the pins. Plate is threadedly mounted on an actuating screw 97 which is secured to the drive shaft 35 of the drum 31.

It is evident that whenever the drum 3i accelerates, the actuating plate 95 will tend to remain stationary, thus creating relative rotary movement between the plate 95 and the screw 97. This movement causes outward threading movement of the plate 95 along the screw 97 to compress the springs 94 which, through pressure plate 91 urge the pressure plate into engagement with the interleaved disks 71 and 75 to compress the same.

However, there is a retarding spring 101 (FIGS. 2 and 5) which functions to prevent such outward threading movement of the actuating plate 95 until the rate of acceleration exceeds a predetermined safe limit. This spring is secured at one end to a lug I03 (FIGS. 5 and 6) on actuating plate 95 and is secured at its other end to a lug I05 (FIGS. 5 and 2) on an adjustment arm I07. The arm is secured to the brake housing 55 in a manner to be presently described.

The spring IOI urges the lug I03 to remain against a lug I08 (FIG. 5) which is carried by the brake housing 55. Thus the spring normally causes the actuating plate 95 to follow the movement of the drum 3] so long as the acceleration rate is below a predetermined limit. Whenever such limit is exceeded, the inertia of the plate 95 causes it to overcome the spring resistance and thread along the screw 97 and cause braking contact between the disks 7] and 75.

The arm 107 tumably fits on the drive shaft 35 (FIG. 2) but is held in a selected position of adjustment by a bolt 109 which thread through the brake housing 55 and fits in one of plural holes I10 (FIG. 5) formed in the am 107. Thus the acceleration safety limit at which the plate will operate can be adjusted by varying the stress on the spring I01.

An auxiliary brake actuator is provided to actuate the brake, if for any reason, the inertia forces do not actuate the plate 95. In addition, this brake actuator is responsive not only to inertia forces but also to the velocity of the drum. Thus if the acceleration is small but steady, the velocity could build up to an objectional value. The auxiliary actuator will cause brake actuation prior to the platform reaching a dangerous descending velocity. The auxiliary brake actuator will, however, not prevent normal operation of the suspended platform.

The auxiliary actuator is best shown in FIGS. 2 and 3 and comprises a centrifugal friction brake. The brake includes a shoe Ill (FIGS. 2 and 7) which is mounted by a pivot II3 on a rotary shoe carrier for movement toward a brake drum 117 under the influence of centrifugal force. The brake proper will be described more in detail presently.

The shoe carrier 115 is driven in the following manner. It is fixed to the lower end of a shaft 121 (FIG. 2) which is mounted by bearings 123 in a gear box housing 125. The housing I25 and drum I17 are shown as being portions of a onepiece casting, the drum being closed by a cover 126 and the box by covers 127 and 128. The carrier shaft I21 carries a bevel pinion 129 engaging a drive bevel gear I30. The latter is fixed to the outer end of a shaft 131 which is mounted by bearings I33 carried by a tubular support member 134 and has a pinion 135 formed on its inner end. The pinion meshes with the teeth of a ring gear 137 (FIG. 2A) which is bolted to the actuating plate 95. It is pointed out that the rotor shaft 131 passes inwardly of the rotary disks 7] (FIG. 2), but passes through aligned holes 139 formed in the fixed disks 75.

Referring now to FIGSv 7 and 8, the shoe 111 is of obtuse angular form having tang-like contact portion 111a disposed in a clevis portion 145 of the shoe carrier 115. The shoe also has a lobe portion 11 1b which acts as a weight to urge the contact portion l 11a against the drum 117 when the lob portion is subjected to centrifugal force. The carrier has a bulging portion 1150 which acts to counterbalance the weight of the lobe lllb so that there is minimum vibration caused by the rotation ofthe carrier and its shoe.

A tension spring 151 urges the shoe lll inwardly against a stop screw 153. The spring has one end hooked over a pin 1S5 carried by a clevis portion 1 1 1c of the shoe 111 and its other end hooked through a hole in the outer end of an adjustment arm 157. The arm extends into a clevis portion 11519 of the carrier and is there mounted on a pivot 159. The position of the arm (and thus the magnitude of the tension exerted by the spring 151) is determined by a screw 161 which is threaded into the carrier 115 and held in place by a jam screw 163.

The stop screw 153 threads into the carrier and is held in a desired position of adjustment by a jam screw 165. The carrier [15 may be retained on the shaft 121 in any manner. A set screw 167 is shown in FIG. 7, the screw being held in place by ajam screw 169.

OPERATION Let it be assumed that for some reason the platform descends at a rate beyond the predetermined safe limit. Normally, the actuating plate of each winch will, because of its inertia, (aided by the inertia of the driven parts of the brake) thread outwardly to compress the associated disks 71 and 75 and halt the descent However, should, for any reason, the plate 95 not move outwardly as it should under the influence of inertia forces, the increasing speed of the carrier 115 (which is indirectly driven by the winch drum) will create sufficient centrifugal force to cause the contact portion 111a of the shoe to engage the drum 117. The resulting frictional drag will create a reverse driving force to drive the plate 95 out wardly. Thus the disk brake will be actuated by the auxiliary actuator.

It is pointed out that the jam-set-screw arrangement shown in FIG. 7 is merely illustrative and other means for obtaining the same results can be utilized. in fact, instead of two set screws, we contemplate utilizing only a single set screw coated with a commercially available fluid locking agent which hardens when the set screw is threaded into place to resist movement of the set screw. The counterweight portion 1150 of the carrier 115 can be cut away to provide access to the single screws MODIFIED FORM OF INVENTION FIG. 9 shows a modified auxiliary actuator in the form of a magnetic eddy current device. The device comprises two rows of permanent magnets 181 carried by a rotor 183 which is mounted on the outer end ofa shaft 1310 for rotation within a steel rotor housing 185. The housing is closed by a cover plate 186 and is mounted on the outer end ofa tubular support 187 which may be identical to support 134 of the first form of the invention. The shaft 131a is supported within support 187 and would be in driving engagement with the ring gear 137 in the same manner as is shaft 131.

The operation of the modified form is as follows: Should the velocity of the winch drum become excessive (without suffcient acceleration to actuate plate 95) the rotor will be driven by the ring gear 137 at such a speed that the eddy currents inof the winch.

Having descnbed the invention in what is believed to be the preferred embodiment of the same, it is desired that it be understood that the invention is not to be limited other than by the provisions of the following claims.

We claim:

1. [n a braking system for a winch drum,

a shaft drivingly connected to said drum,

means providing a rotary connection between said flywheel and said shaft and urging said flywheel to rotate with said shaft but responsive to a predetermined change in velocity of said shaft to permit said flywheel to rotate relative to said shaft and move axially relative to said shaft,

brake means actuated by the axial movement of said velocity responsive means,

and gearing means establishing a driving connection between said velocity responsive means and said flywheel whereby said flywheel can drive said velocity responsive means so that a predetermined velocity of said shaft causes axial movement of said flywheel, whereby axial movement of said flywheel and thus actuating of said brake can be effected by either a predetermined change in velocity or the attainment of a predetermined velocity of said shaft.

2. in a braking system,

a shaft drivingly connected to a rotary member,

means urging said flywheel to move with said shaft but responsive to a predetermined change in velocity of said shaft to permit said flywheel to rotate at a velocity different from the shaft,

brake means actuated by the flywheel upon said difference,

motion multiplying means, and

velocity responsive means connected by said motion multiplying means to said flywheel, and responsive when reaching a predetermined velocity to cause a difl'erence in velocity between said flywheel and said shaft, whereby to actuate said brake so that the brake actuation can be effected either by a predetermined velocity or by a predeten'nined change in velocity of said shaft.

3. In a braking system for a winch drum,

a shaft drivingly connected to said drum,

means providing a rotary connection between said flywheel and said shaft and urging said flywheel to rotate with said shaft but responsive to a predetermined change in velocity of said shaft to permit said flywheel to rotate relative to said shaft and move axially relative to said shaft,

brake means actuated by the axial movement of said and velocity responsive means responsive to a predetermined velocity of said shaft to cause axial movement of said flywheel, whereby axial movement of said flywheel and thus actuating of said brake can be effected by either a predetermined change in velocity or the attainment of a predetermined velocity of said shaft.

4. A braking system as described in claim 3, in which the first named means provides a threaded connection between said flywheel and shaft and urges said flywheel to rotate with said shafl, but is responsive to a predetermined change in velocity in said shafi to permit said flywheel to thread along said shaft and hence move axially relative thereto.

i I I i t 

1. In a braking system for a winch drum, a shaft drivingly connected to said drum, a flywheel, means providing a rotary connection between said flywheel and said shaft and urging said flywheel to rotate with said shaft but responsive to a predetermined change in velocity of said shaft to permit said flywheel to rotate relative to said shaft and move axially relative to said shaft, brake means actuated by the axial movement of said flywheel, velocity responsive means, and gearing means establishing a driving connection between said velocity responsive means and said flywheel whereby said flywheel can drive said velocity responsive means so that a predetermined velocity of said shaft causes axial movement of said flywheel, whereby axial movement of said flywheel and thus actuating of said brake can be effected by either a predetermined change in velocity or the attainment of a predetermined velocity of said shaft.
 2. In a braking system, a shaft drivingly connected to a rotary member, a flywheel, means urging said flywheel to move with said shaft but responsive to a predetermined change in velocity of said shaft to permit said flywheel to rotate at a velocity different from the shaft, brake means actuated by the flywheel upon said difference, motion multiplying means, and velocity responsive means connected by said motion multiplying means to said flywheel, and responsive when reaching a predetermined velocity to cause a difference in velocity between said flywheel and said shaft, whereby to actuate said brake so that the brake actuation can be effected either by a predetermined velocity or by a predetermined change in velocity of said shaft.
 3. In a braking system for a winch drum, a shaft drivingly connected to said drum, a flywheel, means providing a rotary connection between said flywheel and said shaft and urging said flywheel to rotate with said shaft but responsive to a predetermined change in velocity of said shaft to permit said flywheel to rotate relative to said shaft and move axially relative to said shaft, brake means actuated by the axial movement of said flywheel, and velocity responsive means responsive to a predetermined velocity of said shaft to cause axial movement of said flywheel, whereby axial movement of said flywheel and thus actuating of said brake can be effected by either a predetermined change in velocity or the attainment of a predetermined velocity of said shaft.
 4. A braking system as described in claim 3, in which the first named means provides a threaded connection between said flywheel and shaft and urgEs said flywheel to rotate with said shaft, but is responsive to a predetermined change in velocity in said shaft to permit said flywheel to thread along said shaft and hence move axially relative thereto. 